Whining noise while driving

If it is AWD you would have a transfer or PTU so gears are moving when the vehicle is moving. Have you ever had that fluid checked or serviced? If not I'd look there unless your know it is the transmission. Would still check transmission fluid level and change that out too depending on how many miles are on the thing. Check your owner's manual for that. Enjoy!

I had the transmission serviced by the local dealer about 4 months ago. Also checked the fluid level, which is good. The vehicle has around 90,000 miles. Assuming it's the transmission, shouldn't the noise stop if it's in neutral coasting downhill?

it's not AWD by the way.

There is a difference is between a "whine" and a buzzing sound. The buzzing sound, when driving above 40 mph, is due to the front wheel bearings which need to be replaced which is common on Murano's. You can find them on eBay at a very reasonable price (under $100 for both) compared to any dealership around, just find a competent mechanic to do it for you. Ti should take less than 3 hours to replace them.

My 2011 murano is making whinning noise too. I couldn't figure out where it was coming from but a few days ago I realized it would stop if I had the fan recirculation on. I have to figure how to fix it still but at least I know where it's coming from. Maybe it is the same as yours.